An endless cable with balls mounted at spaced distances along the cable for engaging article carriers is shown in the patent to Maimin U.S. Pat. No. 3,134,481, May 26, 1964. Bachmann U.S. Pat. No. 3,422,950, Jan. 21, 1969, discloses an endless single cable conveyor with spaced nylon blocks driven by the teeth of a sprocket having the teeth slotted for reception of the cable therein. A further endless conveyor member with a track providing both the conveying run and the return run is shown in the Juengel U.S. Pat. No. 3,164,245.
While these prior art conveyors can be quite operative for their intended purpose, they all have one or more of the serious disadvantages of considerable cost due to fabrication of specialized parts and materials, the difficulty of reverse bends in the track causing either too much friction or escape of the endless conveyor member from the track, no way to automatically pick-up and securely hold articles or article carrier driving members that are placed upon the track, difficulty in replacing damaged parts, and generally inefficient operation.